May Weather in San Diego, Mexico

Last updated: August 27, 2025

In May, the average temperature in San Diego, Mexico is a pleasant 25°C (77°F). However, be prepared for temperature fluctuations, with minimums dipping to 13°C (56°F) and maximums soaring to 39°C (103°F). Expect a little wet weather as well, with an average precipitation of 59 mm (2.3 in) over 12 days. The atmosphere is quite humid too, with an average humidity of 67%, making for a truly dynamic climate experience.

May Temperature in San Diego

In May in San Diego, the average temperature is 25°C (77°F), with maximums reaching up to 39°C (103°F) and minimums dropping to as low as 13°C (56°F). It's a great time to visit for those who enjoy warm weather, but be prepared for both hot days and cooler evenings.

May Weather in San Diego: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in San Diego, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Diego, May typically has an average temperature of 25°C (77°F), with highs reaching up to 39°C (103°F) and lows dropping to around 13°C (56°F).

Data source: Temperature data for San Diego generated using information from the Copernicus Climate Change Service.

May Precipitation in San Diego

In San Diego in May, the precipitation amount is 59 mm (2.3 in) occurring over the course of 12 days.

May Precipitation Trends in San Diego

The chart displays monthly precipitation patterns in San Diego, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In San Diego, May typically receives around 59 mm (2.3 inches) of precipitation spread over approximately 12 days.

Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

May Humidity in San Diego

In San Diego in May, humidity is 67%. With an average temperature of 25°C (77°F), this humidity feels like traveling through a warm, heavy blanket, making outdoor activities feel more strenuous and sticky than usual.

May Average Humidity in San Diego

This chart illustrates the average monthly humidity levels in San Diego, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in San Diego is approximately 67%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in San Diego

In San Diego in May, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in San Diego, you can check here.

Maximum UV Index Levels in San Diego for May

The chart shows the monthly maximum UV Index (UVI) for San Diego in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In May, the maximum UV index in San Diego typically reaches 14, which falls under the extreme exposure category.

Data source: San Diego May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How May Weather in San Diego Compares to Other Months

Weather in San Diego varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in San Diego, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in San Diego, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	15°C (60°F)	16 mm (0.6 inches)	74%	very high
February Weather	18°C (64°F)	20 mm (0.8 inches)	65%	extreme
March Weather	20°C (69°F)	23 mm (0.9 inches)	58%	extreme
April Weather	23°C (74°F)	22 mm (0.8 inches)	58%	extreme
May Weather	25°C (77°F)	59 mm (2.3 inches)	67%	extreme
June Weather	25°C (76°F)	100 mm (4.0 inches)	76%	extreme
July Weather	24°C (76°F)	85 mm (3.3 inches)	67%	extreme
August Weather	24°C (76°F)	71 mm (2.8 inches)	68%	extreme
September Weather	23°C (74°F)	120 mm (4.7 inches)	81%	extreme
October Weather	21°C (70°F)	121 mm (4.8 inches)	83%	extreme
November Weather	18°C (65°F)	28 mm (1.1 inches)	84%	very high
December Weather	16°C (61°F)	12 mm (0.5 inches)	81%	high